Mexico's foreign minister today dampened hopes of a breakthrough deal at the Cancun climate change talks in November, saying negotiators are focusing on making progress on smaller issues before perhaps seeking a comprehensive agreement in 2011 or later.

Speaking after a two-day meeting in Geneva that dealt with how to pay for carbon-cutting projects in developing countries, Patricia Espinosa said the public should not measure the success of the Cancun talks by whether countries agree on a new legally binding text to combat global warming.

"I don't think this is the right approach under the current circumstances," she told reporters. "Throughout the world there are really very different needs and interests."

Swiss environment minister Moritz Leuenberger, who hosted the closed-door talks in Geneva, insisted countries are "no longer fixated" on agreeing on a successor to the 1997 Kyoto protocol, which scientists say does not go far enough in requiring countries to reduce their carbon emissions.

Delegates traveling to Cancun, a Mexican resort city, should consider it a "unique opportunity to consolidate a cooperative framework that can allow us to move to immediate action," said Espinosa.

Rich countries like the United States, which rejected the Kyoto protocol, want rapidly developing nations such as China and India to join in the effort to cut pollution. Poor countries say they will agree to a deal only if it includes significant financial aid to help them make their economies more green.

Espinosa says such a "green fund" might be agreed in Cancun.

But, according to Wendel Trio, climate policy coordinator at Greenpeace International, big differences remain over where the money should come from, who should get it, and how it would be controlled.

"Given that climate finance is definitely one of the issues that will need to be solved, the fact that we haven't seen progress in the last two days is an indication that governments are not yet willing to move forward," said Trio.

The sums involved are vast – $10bn annually for the next three years, $100bn a year starting in 2020 – and both sides are insisting on transparency to ensure commitments are kept and funds are not wasted.

On Friday, the Dutch government launched a website aimed at tracking pledges made by rich countries and the programmes toward which they go.

Meanwhile, US climate envoy Todd Stern told reporters that failure of a climate bill in the US Senate need not mean the end of attempts to introduce legal restrictions on greenhouse gas emissions in the United States.

"I am in no sense writing off legislation over time and I'm quite sure the president isn't either," he said.

But he rejected any suggestion that the United States might sign up to the Kyoto protocol if no other agreement is agreed to replace it.